Chittagong University of Engineering & Technology

About: Chittagong University of Engineering & Technology is a education organization based out in Chittagong, Bangladesh. It is known for research contribution in the topics: Computer science & Renewable energy. The organization has 1200 authors who have published 1444 publications receiving 10418 citations. The organization is also known as: Engineering College, Chittagong & Bangladesh Institute of Technology, Chittagong.

Nonlinear time fractional Korteweg-de Vries equations for the interaction of wave phenomena in fluid-filled elastic tubes

Abstract: This work investigates the wave-wave interactions by considering two-sided time fractional Korteweg-de Vries equations (TFKdVEs). The generalized $\exp(-\Phi(\xi))$ -expansion method (GEEM) along with Khalil's fractional derivatives is employed to divulge several types of scattered wave solutions of TFKdVEs. It is found that the fractional parameters significantly modified the interaction of nonlinear wave dynamics. The results obtained may be useful for clarifications of the interaction between two waves not only in non-conservative fluid-filled elastic tubes but also in shallow water and plasma physics.

Feature Extraction from Dermoscopy Images for an Effective Diagnosis of Melanoma Skin Cancer

Abstract: The aim of this paper is to extract some distinct geometric features from dermoscopy images to classify benign and malignant melanomas. To avoid skin biopsy which is an invasive technique, diagnosis of melanoma skin cancer from dermoscopy images was developed. It is a very challenging task due to some reasons. Firstly, high degree of intraclass variation exists among melanoma images while low interclass variation is found between melanoma and non-melanoma images. Secondly, benign and malignant melanoma images are visually similar to a great extent. And finally noises like hair are always present in skin images which make difficult to analyse the images. In this work, we used fundamental ABCD rule to detect malignant melanoma and benign lesion based on quantitative measures. In our proposed technique, we extracted a new feature which is the difference between maximum and minimum Feret diameters of the best fit ellipse to skin lesion. This discriminative feature alone classified the melanomas with 86.5% accuracy. In our approach, we applied the feature extraction block containing all parameters to 200 images and the overall accuracy of 98% was achieved to detect malignant and benign melanoma from the images. A Back-propagation Neural Network (BNN) model was developed and eventually used as a classifier in this proposed method.

High performance ultra-thin CdTe solar cell with Lead Telluride BSF

Abstract: The polycrystalline cadmium telluride (CdTe) is a leading photovoltaic (PV) material for the possibility of high-efficiency and low-cost thin film solar cell. The absorber material CdTe has a high absorption coefficient over 5×10 5 /cm and it has a direct bandgap of 1.45 eV, which is very close to the optimum bandgap for solar cells. In this work, numerical analysis was done utilizing AMPS (Analysis of Microelectronic and Photonic Structures) simulator to investigate the possibility of ultra-thin absorber layer of CdS/CdTe solar cell. In the proposed cell the CdTe layer was reduced and found that 1 μm CdTe layer is enough for acceptable range of cell conversion efficiency. The viability of this ultra-thin CdTe absorber layer was examined, together with 0.1 μm PbTe back surface field (BSF) layer to reduce the barrier height in valence band and to minimize the recombination losses at the back contact of the CdS/CdTe cell. It was found that the proposed ultra-thin cells have conversion efficiency of 21.11% (Voc = 1.04 V, Jsc = 23.509 mA/cm 2 , FF = 0.863) without BSF and with 100 nm PbTe BSF conversion efficiency increased to 21.83% (Voc = 1.05 V, Jsc = 23.895 mA/cm 2 , FF = 0.87) with only 0.8 μm of CdTe layer. Moreover, the normalized efficiency of the proposed cells linearly decreased with the increasing operating temperature at the gradient of -0.4%/°C, which indicated better stability of the cells with and without BSF.

Nonlinear ion acoustic solitary waves with dynamical behaviours in the relativistic plasmas

Abstract: This work investigates the basic features of Nonlinear Ion Acoustic Solitary waves (NIASWs) and their dynamical behaviours in an unmagnetized relativistic collisionless plasma system via the Schamel Korteweg-de Vries (SKdV) equation. Such plasma is composed by the generalized distributed electrons, Boltzmann distributed positrons and relativistic warm ions. The influences of plasma parameters on NIASWs and their dynamical behaviours are investigated by comparing 26−term expansion of relativistic Lorentz factor (RLF) with both of weakly (2−term expansion of RLF) and highly (3−term expansion of RLF) regimes. It is found that the 26−term expansion of RLF are significantly changed NIASWs instead of both weakly and highly relativistic regimes. Therefore, the theoretical results would be very useful for understanding the nature (amplitude, width, polarity, etc.) of wave dynamics not only in astrophysical and space environments but also in further laboratory studies, where the proposed plasma assumptions are existed.